1. Field of the Disclosure
The invention relates to a device for manufacturing plastic parts, in particular plastic parts consisting of several individual parts, according to the preamble of the independent patent claims.
2. Related Art
Devices are known form the state of the art, which are suitable for manufacturing parts which consist of one or more plastic components.
The European patent EP 1 155802 of the same applicant shows an injection moulding device with two production planes (parting planes) with a rotary system which is arranged between a stationary and a moving mould part, and serves for holding a middle mould part. The middle mould part is held by a lower and an upper crossmember by way of holding means and is movably arranged about a vertical axis. The cross-members arc guided on the tic-bars of an injection moulding machine. In order to compensate, the weight of the middle mould part, the lower crossmember, when required, is supported on the machine bed of the injection moulding machine. The holding means are arranged displaceable relative to one another, so that the middle mould part may be exchanged. In a first production plane, a first material component is injected into a cavity so that a first part arises. The part of the first material component remains sticking to the middle mould part on opening the mould, and is brought with this into the second production plane by rotating the middle mould part, where, after the closure of the mould, it is actively connected to a second material component The middle mould part is supported on the tie-bars of an injection moulding machine by way of holding devices.
EP089S848 from Ferromatik Milacron Maschinenbau GmbH shows a further device with two parting planes. A middle mould part is arranged between a stationary and a movably arranged mould part, and this middle, mould part is mounted in a lower and an upper crossmember, and is supported on a machine bed of an injection moulding device. The middle part is rotatably arranged about a vertical axis by 180° and comprises cavities only on two sides. The bearing in the region of the upper crossmember may be opened, so that the middle part may be removed.
EP 1110449 (hereinafter EP'449) of Krauss Maffei Kunstofftechnik GmbH shows an injection moulding device with two production planes, with a stationary and a movable mould half A mould middle part is arranged between the two mould halves, and is held on one side by way of a guide admitted in the machine bed of an injection moulding machine, and is rotatably arranged about an axis. The injection moulding machine is adapted to meet these special demands. The device described in EP'449 is suitable for manufacturing parts of several plastic components.
In PCT/DKOI/0699 (hereinafter PCT699), of Jes Gram, the basic concept for a method with which an assembly of two identical parts is effected by welding these to one another in at least one parting plane is described. The device suggested for implementing the method comprises two middle parts which in each case are rotatably arranged about an axis, and which may be opened and closed with the injection mould. PCT699 generally describes a device for manufacturing a single hollow body, in that a first half shell is manufactured in a first injection moulding plane, and a second half shell in a second injection moulding plane, and then by way of rotating the middle parts about their axes by 180° and subsequent closure of the injection mould with a uniformly opened mould, i.e. both parting planes are opened symmetrically, are connected to one another with a material fit. The material-fit connection between the two half-shells is effected by way of joining the melted base material as a result of the closure movement of the mould. A heat source is applied for the melting, which is placed laterally next to the device. A single hollow body arises per cycle. In particular, one may not deduce from PCT699 how the middle parts have to be mounted in the injection mould, so that a perfect functioning may be ensured. The device suggested in PCT'699 for implementing the method provides no answers to questions which arc essential for carrying out the method_ The man skilled in the art has no hint from PCT'699, amongst other things also on account of the very schematic, imprecise description, as to how a device for successfully implementing the method should look in detail.
U.S. Pat. No. 4,744,741 (hereinafter U.S. 741), John B. Glover et at, shows a device with a stationary first mould half and a second mould half which is movably arranged with respect to this. A first and a second, middle part in each case rotatable about an axis are arranged between these two mould halves, and these middle parts cooperate in the middle with a direct positive fit and form the inner part of a cavity. A further mould part consisting of two mould halves in the closed condition is arranged about the rotatable middle parts and temporarily forms an outer annular part of an injection mould. In the middle, the two rotatable middle parts cooperate directly along a middle parting plane. Two first parts are manufactured simultaneously in a first and third parting plane. The device is subsequently opened in a uniform manner and the two first parts, by way of the rotatable middle parts, are joined together with a second part which is held by the middle, annular mould part. According to the description, the two first parts arc still in the part-plastic condition when they are connected to the first part, so that the first and the second part stick to one another. An external heating is provided in the case that the material is no longer sufficiently fluid, in order to melt the material again. The device described in U.S.'741 serves for manufacturing tube unions or tube connection pieces which arc to be pushed over the ends of tubes to be connected, and comprise seals which are manufactured in the same device and arc connected to the outer part in the above described way and manner by way of the rotatable middle parts. The exact construction of the injection mould described in U.S.'741 as well as their coordination may not be deduced from the document Amongst other thing, one may not deduce from the description as to what the demands on an injection moulding machine are.
A significant disadvantage of the devices known from the state of the art lies in the fact that parts are joined together via the main tool movement by way of the closing of the mould. This leads to a low precision and a slowing of the process, since the closure mechanism of the injection moulding machine which is responsible for the closure movement is not suitable for assembly. Furthermore, with a device with a multitude of cavities per closure plane, it is not possible to assemble in an individual manner.